To effect cutting on a worksheet, the positioning of a laser cutting head relative to the worksheet has to be accurate. In a combination laser punch press machine, due to the vibrations caused by the punching of the worksheet, the positioning of the laser cutting head, not to mention the laser resonator (or generator), the beam guide and the beam bender, may become misaligned. There are a number of attempts to maintain the alignment of the laser cutting head with respect to the worksheet in a combination laser punch press machine. These are disclosed for example in U.S. Pat. Nos. 4,833,292, 4,873,418, 4,889,968 and 4,940,880.
In the '292 patent, to overcome the vibrations caused by the punching of the worksheet, the punch press and the worktable are provided on separate frames. And the laser system is placed on the same frame as the worktable. The problem with this system is that the worktable is movable. Further, the carriage and clamps that hold the workpiece and move the workpiece along the surface of the worktable also tend to create vibrations. As a consequence, the position of the laser cutting head of the laser of the '292 patent nonetheless is affected by the respective movements of the worktable and the worksheet thereon.
The '418 patent is a continuation-in-part of the '292 patent. It also discloses the placing of the laser system on the same frame as the moveable worktable.
For the combination laser punch machine disclosed in the '968 patent, the laser system is mounted on a vibration proof frame, which in turn is mounted on top of the frame where the turret punch press is mounted. To eliminate vibrations, a plurality of positioning support devices are interposed between the laser generator and the isolation support. Adjustment required for the laser system is rather complicated for the '968 machine.
The '880 patent likewise discloses a combination punch press and laser cutting machine. But the '880 machine is disclosed to have a C-shaped punch press frame and a platform extending at its rear portion to which the laser beam generator is mounted.